1. Field of the Invention
The present invention relates to a belt-loop sewing machine which is capable of efficiently supplying a belt loop to a sewing position.
2. Description of the Related Art
As disclosed in U.S. Pat. No. 5,588,384, a belt-loop sewing machine has been known which is capable of sewing a multiplicity of belt loops through which a belt is allowed to pass through, onto the waist of a variety of sewed products, such as jeans and skirts. In general, the belt-loop sewing machine is provided with a belt-loop supply unit for automatically supplying the belt loop to the sewing position.
A conventional belt-loop sewing machine 1 shown in FIG. 20 incorporates a machine body 2 and a belt-loop supply unit 3.
The machine body 2 is a cycle machine having two needles and incorporating a needle plate 9 disposed on the upper surface of a machine bed 5. Two parallel needles 7 disposed in the lengthwise direction of a machine arm 6 are joined to a needle bar 8 allowed to vertically be moved by a known needle-bar moving mechanism (not shown) which is operated in synchronization with rotations of an upper shaft. The machine arm 6 is provided with a known cloth retaining unit (not shown) for supporting two presser feet 10,10 vertically movable up and down relative to a needle plate 9. Thus, the waist portion of trousers or the like placed to surround the machine bed 5 can be held between the each presser feed 10, 10 and the needle plate 9.
An operator faces a free end of the machine arm 6 of the machine body 2 when the operator performs the sewing operation. The free end is defined an operator side OS and opposite side is defined a back side BS for convenience. The belt-loop supply unit 3 is disposed in the right-side portion when it is viewed from the operator side OS of the machine body 2. The machine body 2 and the belt-loop supply unit 3 are disposed on a sewing table (not shown).
The belt-loop supply unit 3 has a tape supply means 13 for delivering an elongated tape 12 for forming belt-loop from the back side BS to the operator side OS in the lengthwise direction of the machine body 2. Then, the tape supply means 13 cuts the delivered tape 12 at its proximal end to have a predetermined length so as to form a belt-loop. Moreover, the belt-loop supply unit 3 has a loop supply means 20 which holds portions adjacent to the two ends of the belt-loop having the predetermined length to bend the ends of the belt-loop and moves the belt-loop to the sewing position of the machine body 2.
The tape supply means 13 incorporates a tape delivery frame 14 on which the tape 12 delivered from a tape supply source (not shown) is placed on the upper surface thereof. A delivery roller 15 serving as a tape delivering means is disposed above the tape delivery frame 14. The delivery roller 15 can be brought into contact with the upper surface of the tape 12.
The delivery roller 15 is formed in a disc-like shape having an outer surface provided with a plurality of teeth 16 for delivering the tape 12. The delivery roller 15 is rotated/stopped by a tape delivering motor (not shown). A tape cutting means 17 is disposed at a position adjacent to the leading end of the tape delivery frame 14 disposed downstream (indicated with an arrow B shown in FIG. 20) in a direction in which the tape 12 is delivered, the tape cutting means 17 being structure to cut the base portion of the tape 12 to form a belt-loop (not shown) having a predetermined length. The tape cutting means 17 incorporates a movable blade 17a which is usually disposed above the movement passage for the tape 12 and which is able to move vertically by a cutting drive means (not shown), such as a cylinder, after the tape 12 has been fed for a predetermined length. Moreover, the tape cutting means 17 incorporates a fixed blade (not shown) disposed below the movement passage for the tape 12.
A pair of front and rear L-like shaped tape receiving members 18 are, as a tape support means, disposed to support, from lower sides, the belt-loop having the predetermined length supplied by the delivery roller 15 of the tape supply means 13. The position supported by the tape receiving members 18 is called a belt-loop forming position P4. A guide rod 19 having a lower portion bent into an L-shaped is disposed between the tape receiving members 18. The guide rod 19 aligns the side edge of the tape 12 supplied to the belt-loop forming position to a predetermined position. When the two ends of the belt-loop cut to have the predetermined length are bent by a leading end 21a of a bending shafts 21 to be described later, the guide rod 19 prevents deviation of the bent portions, that is, causes the bent portions to completely be superimposed.
The loop supply means 20 has right and left bending shafts 21 each having a forked leading end 21a. Each of the bending shafts 21 can be rotated around the axis thereof and moved in the axial direction by a fork drive means (not shown), such as an air cylinder. The leading ends 21a of the binding shafts 21 hold end portions of the belt-loop held by the tape receiving members 18 with the predetermined length. Then, the bending shafts 21 are rotated downwards to bend the end of the belt-loop by an angular degree of 180.degree.. Then, the bending shafts 21 are moved forward so that the belt-loop is positioned to the sewing position. The leading ends 21a of the bending shafts 21 are always disposed at retracting positions apart from the belt-loop forming position P4 to the right side when the leading ends 21a are viewed from a position adjacent to the operator side OS.
The tape delivery frame 14 is provided with a thickness detecting means 22 for detecting a stepped portions or the like of the tape 12 and whether or not a tape 12 has been placed on the tape delivery frame 14.
The conventional belt-loop sewing machine 1 structured as described above causes the tape 12 to be delivered from the upper surface of the tape delivery frame 14 to the belt-loop forming position P4 owing to the rotations of the delivery roller 15. Then, the tape 12 is supported by the tape receiving members 18 from lower side. At this time, the thickness detecting means 22 detects the stepped portion of the tape 12 which is moving on the tape delivery frame 14 to remove the failed belt-loop, and whether or not the tape 12 exists to urge the supply of the tape 12.
Then, the tape 12 delivered by the guide rod is moved and aligned to the standing portions of the tape receiving members 18. Then, the bending shafts 21 are moved forward toward the belt-loop forming position so that the tape 12 is inserted into a forked portion at the leading ends 21a of the bending shafts 21. Then the tape cutting means 17 cuts the proximal end of the tape 12 so that a belt-loop having the predetermined length is formed.
Then, the bending shafts 21 are rotated such that the two ends of the belt-loop are bent by an angular degree of 180.degree.. Then, the bending shafts 21 are moved in the axial direction so as to move the belt loop from the belt-loop forming position to the sewing position on a sewed product S. Then, the presser feet 10 are moved downwards to press the sewed product S and the two end bent portions of the belt loop against the needle plate 9. Then, the bending shafts 21 are moved rearwards so as to be removed from the belt loop. Then, the upper surfaces of the two end bent portions of the belt loop are sewed so that the belt loop is sewed onto a predetermined position of the sewed product S.
After the bending shafts 21 have been moved rearwards, the bending shafts 21 are rotated inversely to restore the initial state of the bending shafts 21. Then, a subsequent operation similar to the foregoing operation is performed so as to form a belt loop which must be sewed next. Then, the bending shafts 21 are brought to be on standby at a standby position which is in front of the sewing position.
The foregoing conventional belt-loop sewing machine is in a state that the tape 12 has been delivered to the belt-loop forming position during forward movement of the bending shafts 21 in the axial direction to move the belt loop to the sewing position. Since the bending shafts 21 are moved forwards and rearwards in the axial direction through the same passage, the bending shafts 21 are brought into contact with the tape 12 which has been delivered to the belt-loop forming position. Therefore, the tape 12 is loosened or deviation of the position occurs. As a result, when the tape 12 is cut, the tape 12 cannot be cut to have the predetermined length. The lengths of the belt loops cannot be made consistently. The tape 12 cannot be sometimes inserted into the space between the forks at the leading ends 21a of the bending shafts 21. In this case, the belt loop cannot be formed.